Soldering iron



FIG. 1 is a top plan view of a soldering iron showing my new design;

FIG. 2 is a side elevational view thereof, the side opposite being a mirror image;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is an enlarged rear elevational view thereof; and

FIG. 5 is an enlarged front elevational view thereof. 

The ornamental design for soldering iron, as shown and described. 